ADSP-2126x SHARC Processor Hardware Reference
10-13
Serial Peripheral Interface Port
The SPI port supports both Master mode and Slave mode DMA. The fol-
lowing sections describe Slave and Master mode DMA operation, DMA
chaining, switching between transmit and receive DMA operations, and
processing DMA interrupt errors.
Do not write to the
TXSPI
register during an active SPI transmit
DMA operation because DMA data will be overwritten. However,
writes to the
TXSPI
register during an active SPI receive DMA oper-
ation are permitted. The
RXS
register is cleared when the
RXSPI
register is read. Reads from the
RXSPI
register are allowed at any
time during transmit DMA. Interrupts are generated based on
DMA events and are configured in the
SPIDMAC
register.
Similarly, do not read from the
RXSPI
register during active SPI
DMA receive operations.
In order for a transmit DMA operation to begin, the transmit buffer must
initially be empty (
TXS
= 0). While this is normally the case, this means
that the
TXSPI
register should not be used for any purpose other than SPI
transfers. For example, the
TXSPI
register should not be used as a scratch
register for temporary data storage. Writing to the
TXSPI
register via the
software sets the
TXS
bit.
When the SPI DMA engine is configured for transmitting:
1. The receive interface cannot generate an interrupt, but the status
can be polled.
2. The four-deep FIFO is not available in the receive path.
Similarly, when the SPI DMA engine is configured for receiving,
1. The transmit interface cannot generate an interrupt, but the status
can be polled.
2. The four-deep FIFO is not available in the transmit path.
Summary of Contents for ADSP-21261 SHARC
Page 30: ...Contents xxx ADSP 2126x SHARC Processor Hardware Reference ...
Page 40: ...Register Diagram Conventions xl ADSP 2126x SHARC Processor Hardware Reference ...
Page 58: ...Differences From Previous SHARCs 1 18 ADSP 2126x SHARC Processor Hardware Reference ...
Page 112: ...Secondary Processing Element PEy 2 54 ADSP 2126x SHARC Processor Hardware Reference ...
Page 178: ...Summary 3 66 ADSP 2126x SHARC Processor Hardware Reference ...
Page 204: ...DAG Instruction Summary 4 26 ADSP 2126x SHARC Processor Hardware Reference ...
Page 322: ...Setting Up DMA 7 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 436: ...SPORT Programming Examples 9 86 ADSP 2126x SHARC Processor Hardware Reference ...
Page 521: ...ADSP 2126x SHARC Processor Hardware Reference 11 31 Input Data Port rts IDP_ISR end ...
Page 522: ...Input Data Port Programming Example 11 32 ADSP 2126x SHARC Processor Hardware Reference ...
Page 590: ...Timer Programming Examples 14 20 ADSP 2126x SHARC Processor Hardware Reference ...
Page 796: ...I O Processor Registers A 174 ADSP 2126x SHARC Processor Hardware Reference ...
Page 800: ...B 4 ADSP 2126x SHARC Processor Core Manual ...
Page 846: ...Index I 36 ADSP 2126x SHARC Processor Hardware Reference ...